For some reason I no longer get push notifications from my ZOHO mail app on my Samsung Galaxy S6 Android ver. 6.0.1

It just started today, I uninstalled and re-installed the app... still no notifications.   Web portal works fine... I see the emails come in without having to refresh page....   The only way I can see new emails on phone is by clicking ZOHO mail app icon and refreshing.

Please advise.

John C.